ELIGIBILITY OF ALZHEIMERS-DISEASE CLINIC PATIENTS FOR CLINICAL-TRIALS

OBJECTIVES: To identify the percentage of patients with Alzheimer's di sease (AD) in a general clinic population who would be provisionally e ligible for randomized clinical trials and the extent to which these p atients represent the overall clinic-based population. BACKGROUND: Man y randomized clinical trials have restricted enrollment criteria that may limit generalizability, i.e., AD patients who fulfill selection cr iteria for phase III clinical trials map not be representative of othe r AD patients in clinical settings. DESIGN AND SETTING: Patients diagn osed as probable or possible AD from the nine clinical sites of the St ate of California's Alzheimer's Disease Diagnostic and Treatment Cente rs (ADDTC) were selected on the basis of their provisionally fulfillin g the inclusion and exclusion criteria of two typical AD clinical tria ls at the time of their first visit (EGG and brain imaging criteria we re not available). RESULTS: From a sample of 3470 subjects with possib le or probable AD, overall, only 4.4% or 7.9% would have been provisio nally eligible for each of two trials. Patients provisionally eligible were younger, relatively underrepresented by women, better educated, wealthier, and more likely to be white than ineligible patients. The m ajor independent demo graphic predictors for eligibility were (1) inco me greater than $15,000 per year, (2) male gender, and (3) college edu cation. More than 60% of probable AD patients were excluded because of significant behavioral problems; approximately one-quarter each were excluded because of significant medical or neurological problems. Allo wing patients with probable or possible AD to enroll would have result ed in 10.6% being eligible. CONCLUSION: Selection criteria for AD clin ical trials result in a demographically and clinically constrained sub group that is not representative of the overall clinic population.